| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical waveguide or the like in which spatially incoherent light beams are converged into regions having small diameters. SOLUTION: An optical waveguide 10 has an axis 11 which is extended from a first tip 110 to a second tip 120 in a linear or curved manner. The cross section, which is vertical to the axis 11 of the optical waveguide 10, includes a circular first region that includes the axis 11 and has an average refractive index N<SB>1</SB>, a ring shaped second region that surrounds the first region and has an average refractive index N<SB>2</SB>and a ring shaped third region that surrounds the second region and has an average refractive index N<SB>3</SB>. The number of the waveguide modes of the light beams which are guided in the core regions along the axis 11 is equal to or greater than 100 and a relationship equation of S<SB>2</SB>/S<SB>1</SB>≤0.5 is satisfied, wherein S<SB>1</SB>is the cross-sectional area of the core region at the first tip 110 and S<SB>2</SB>is the cross-sectional area of the core region at the second tip 120. COPYRIGHT: (C)2005,JPO&NCIPI |
